I would not turn it off every few minutes like that. That can put wear and tear on the motor of the machine.
When I turn my machine on it gets turned off when I'm through sewing and don't worry about it even if I am pinning, ironing, whatever in between.
I've never had problems with having to replace light bulbs because of leaving it on. I've been sewing more than two years with some machines and have yet to replace light bulbs.
Electric company will tell you turning on and off switches of any kind will not save you electricity but rather use more because of the on and off switch and harder on your electrical circuits so seems to me it will be the same for any electronic machine such as this.